CAIRO — Egypt’s prime minister-designate pledged on Thursday that his new 35-member Cabinet would be a “people’s government” and called on Egyptians to rally behind it and the nation’s newly elected president in the face of “grave challenges.”

The U.S.-educated Hesham Kandil also confirmed that Hosni Mubarak’s defense minister of 20 years, Field Marshal Hussein Tantawi, will retain the post. Tantawi led the military generals who took over from Mubarak when the president stepped down nearly 18 months following a popular uprising.

The new government, due to be sworn in later Thursday, is the first since Mohammed Morsi, a longtime Muslim Brotherhood leader, was inaugurated as Egypt’s first freely elected president. The new Cabinet’s line-up appeared aimed at allaying worries that Islamists will monopolize power in the government — three Brotherhood members were given ministries and several members of the outgoing, military-backed government will retain their posts, including the foreign and finance ministers.

Still, the line-up fell far short of the unity government that Morsi had initially said he would put together, bringing together political factions. Instead, the members were largely technocrats. And many will be looking to see how many of the new ministers, while not Brotherhood members, are Islamists or sympathetic to the movement to gain a real picture of the government’s diversity.